Multiple discharge tube



Oct. 22, 1935. A. NYMAN MULTIPLE DISCHARGE TUBE Filed Dec. '7, 1929 R w m V m J 4 w 4 0 6 4 5 v a HTTORNEY Patented Oct, 22, 1935 UNITED STATES MULTIPLE DISCHARGE TUBE Alexander Nyman, Dobbs Ferry, N. Y., assignor, by mesne assignments, to Radio Corporation of America, a corporation of Delaware Application December 7, 1929, Serial No. 412,506 In Germany August 14, 1929 12 Claims.

This invention refers to a multiple discharge tube, especially to vacuum tubes in which a plurality of individual electrode systems are arranged within a common vessel or envelope interconnected by coupling elements to constitute an equivalent for a multi-tube arrangement.

The object of this invention consists in providing a multiple radio tube, which possesses a. number of advantages as compared to tubes of this kind hitherto used in practice.

A further object of the invention consists in providing a multiple vacuum tube in which the individual electrode systems are arranged in such manner that the mutual capacity between the electrodes belonging to different electrode systems are utilized as a coupling means between such systems.

A further object of the invention consists in providing a multiple radio tube in which the mechanical arrangement of the supporting structure for the electrode systems,isconsiderablysimplified as compared to the tubes of this kind hitherto employed in radio art.

Further objects and advantages of the invention in operation, as well as in arrangement of its parts, will be, in part, obvious and, in part, specifically pointed out in the description of the invention hereinafter set forth, which, taken in connection with the accompanying drawing, discloses a preferred embodiment thereof. Such embodiment, however, is to be construed merely as illustrative of the broad principle of the invention, which is subject to many modifications,

coming within the broad terms as comprised by the appended claims.

Figure 1 shows in a schematic way the structural arrangement of a multiple vacuum tube constituting one form of embodiment of my invention.

Figure 2 is a cross-section of the tube illustrated by Figure 1.

Figure 3 is a diagrammatic representation of a multiple tube of the kind illustrated by Figure 1, showing in a more lucid manner the arrangement of the electric circuits.

Figure 4 is a fragmental part of Figure 1, showing a preferred form of the relative arrangement of the grid and anode electrodes of successive electrode systems.

Similar reference numbers refer to similar elements throughout the dilferent views of the drawing.

In the known multiple vacuum tubes, a plurality of electrode systems, similar to the systems as used in the usual type single vacuum tubes, are arranged side by side and inter-connected by suitable coupling elements. For this purpose, preferably, resistances and condensers are arranged between the individual electrode stages, as it was found that this kind of resistance coupling is the 5* most suited for use in connection with multiple tubes of the kind under consideration. Such a construction of the electrode systems side by side, however, necessitates a complicated supporting structure for the electrodes, which entails a comparatively high manufacturing cost and decreases the operating dependability of such tubes.

In accordance with the present invention, the entire inner structure of the multiple tube is considerably simplified by arranging the electrodes of difierent systems in such a manner, relative to each other, that a capacitative coupling exists be tween these electrodes, which is utilized to serve as coupling capacity and makes it possible to dispense with a special coupling condenser to be arranged within the tube. Furthermore, in accordance with this invention, the electrodes of the individual systems fulfilling an equal task are mounted to a common support and provided with common resistance elements, which results in an extremely simple structure of the entire tube.

Referring more particularly to Figure 1 of the drawing, the arrangement of the electrodes is shown as being reversed, as compared to the usual arrangement, in that the heating system is 39 mounted at the outside and the anode system is arranged at the inside of the electrode arrangement to secure the advantages of the principle of my invention, although such reversal is only incidental and need not be utilized. A supper member or tube l of metal is surrounded by a number of electrodes 3, placed side by side and constituting anode electrodes. The support member l is surrounded by an intermediate layer 2, which will be referred to later'on in more detail. 40 The grid electrodes are designated by numeral.

4 and are supported by rods 5. The whole arrangement is surrounded by a heating coil 1, which serves to maintain the cathode at a temperature for electron emission by indirect alternating current heating.

Referring more particularly to Figure 3, the usual connection of a resistance coupled multiple tube is chosen in the arrangement, as described in Figure l. The anode circuits of the individual units include resistances 2, which are connected to the lead I. This lead 1 serves to sup ply the anode voltage from the battery a. The grid circuits of the grids 4 include grid leads 6. .In the usual circuit arrangement, as used according to the conventional practice, each anode is connected to the grid of the succeeding unit by means of a condenser. According to the present invention, however, such condenser is entirely dispensed with, so that no special condenser has to be arranged within the tube and the coupling between the anodes and the succeeding grid is effected by the inherent capacity between such anode and the antecedent grid electrode, constituting a novel arrangement of the multiple vacuum tube, in accordance with the invention. The inherent capacities between the anodes and succeeding grid electrodes are indicated at c in Figure 3 by means of dotted lines. The cathode, in accordance with the example illustrated by the drawing, is heated indirectly by means of alternating current, the heating arrangement comprising a heating coil 1 which is wound on a tube 8 of refractory material integral with a conducting tube 9, with a layer 9'' of electron emitting substance applied thereto, which serves as a cathode. The tube 5 is connected to the minus pole of the anode voltage source a. The free ends of the grid leak 6 are connected together and joined across a grid bias voltage g to the minus pole of the anode voltage source a, in a manner well known in practice. The input circuit of the tube is comprised by the oscillatory circuit including an inductance f3 and variable capacity M and the output circuit, which is coupled to the last anode resistance of the last electrode system, includes a transformer l5 for the translation of the arm plifying electric currents for further utilization. The input circuit [3, l4 may, for instance, be the oscillatory circuit of the radio receiving system and receive the high frequency oscillations picked up by an antenna arrangement, which oscillations are amplified by the tube and may be utilized in the output circuit for operating a translating device such as a loud speaker after rectification and eventualfurther low frequency amplification.

Returning to the structural embodiment of the invention illustrated by Figures 1 and 2, the resistances 2 and 6 are arranged in a special manner, so that the supporting members for the electrodes serve, at the same time, as resistance elements. The anode resistances are obtained in the following manner. A layer of resistance material 2 is applied to the anode support I upon which .the rings'3, constituting the individual anodes, are mounted. The anode voltage is applied to the support or tube l by means of a lead I connected to the positive pole of the anode batteryu. The grid wires 4 are arranged in a similar manner, in that the metal rod 5 is surrounded by a layer of resistance material 6, so that the resistance is placed between thelead 5 and the grids 4. Thegrid of the first tube unit is connectedto the input circuit by means of lead. 12. The heating system is the well known alternating current heating, arrangement. the windings 1 of the. heating coil being wound upon a Cylinder 801? refractory material. In order to prevent the production of a magnetic field within the heating coil, this latter is wound in such a manner that the individual fields produced by alternate turns cancel each other, which, in the art, is otherwise called bifillary winding. The inside of the cylinder carries the conducting tube 9, which is covered with a layer of electron emitting substance 9. The. tube 9 is connected to anode voltage battery. The entire structure of the individual units is surrounded by a glass bulb or vessel with a press I! for the supporting of the outside leads of the electrodes. The leads are designated by the same index numbers as the corresponding electrodes.

In a preferred arrangement of the invention the grid electrodes are displaced somewhat in respect to the anodes, in order to increase their capacitative coupling. In order to furthermore increase the mutual capacity, ring It or similar elements may be arranged close to the grid wires, such as is more particularly illustrated in Figure 4.

The inherent capacity between the anode electrodes and the succeeding grid electrodes has been found to be sufiiciently high to produce an effective coupling between successive tube stages. The invention, however, is of special advantage for high frequencies, whereby the capacity effect increases considerably, as is well known accord-- ing to electrical theory.

Although my invention has been described in reference to the specific example of the embodiment illustrated by the drawing, it is apparent that the invention may be practiced in a variety of forms and constructions. all coming within the broader scope of the terms of the claims- What I claim is:-

l. A multiple electric discharge device comprising a vessel; a plurality of discharge paths arranged within said vessel, each having main electrodes and a control electrode, the output electrode of one unit being disposed adjacent to the control electrode of the succeeding unit; said output electrode and control electrode cooperating to provide a capacity coupling unit between successive discharge paths.

2.. A multiple electric discharge device comprising an evacuated vessel; a plurality of discharge units arranged within said vessel, each comprising a cathode, anode and a control electrode, the anode of one unit being disposed adjacent to the control electrode of the succeeding unit; said anode and control electrode cooperating to provide a capacity coupling unit.

3. A multiple thermionic discharge device comprising an evacuated vessel; a plurality of discharge units, eachcomprisingan anode, cathode,

and a grid electrode, the anode electrodes of said units being disposed adjacent to the grid electrodes of the succeeding unit; said anode and grid cooperating to provide a capacity unit, said device iurther comprising coupling impedances mounted within said vessel and connected to said anodes; and a common outside terminal lead from the free ends of said impedances.

1. A multiple thermionic discharge device comprising an evacuated vessel; a plurality of amplifying units arranged within saidvessel, each comprising a cathode, anode and a grid electrode; individual coupling resistors for said units mounted within said vessel and connected to the anodes of said units; common connecting leads from the free terminals of said resistors and from said cathodes to the outside of said vessel; grid leak resistors connected between the grid electrodes and the cathodes of said units also mounted within said vessel; the anode of one unit being disposed adjacent to the grid of the succeeding unit, said anode and grid cooperating to provide a capacity coupling unit together with coupling and grid leak resistors.

5. A multiple thermionic discharge device comprising an evacuated vessel; a plurality of amplifying units arranged within said vessel comprising a common cathode and individual cooperating anode and grid electrodes; coupling resistors mounted within said vessel and connected to said anodes; common connecting leads from the free terminals of said resistors and from said cathode to the outside of said vessel, said grid electrodes being mounted adjacent to the anode of the preceding unit, said anode and grid cooperating to provide a capacity coupling unit.

6. In a multiple thermionic discharge device as claimed in claim 5, a common conducting support covered with, a layer of insulating material carrying said anode electrodes whereby said insulating layer serves to act as coupling resistors and whereby said common lead is connected to said conducting support.

7. In a multiple thermionic discharge device as claimed in claim 5, a common conducting support covered with a layer of insulating material carrying said grid electrodes whereby said insulating layer serves to act as grid leaks and a common lead from said support to the outside of said vessel.

8. A multiple thermionic discharge device comprising an evacuated vessel; a common cathode arranged within said vessel comprising a cylinder of refractory material; a heating coil mounted upon said cylinder, and a layer of electron emitting substance applied to the inside surface of said cylinder; a conducting cylindrical support mounted within and coaxially with said cylinder; a coating of high resistance material applied to said cylinder; a plurality of ring-shaped anode electrodes mounted upon said resistance layer in spaced relationship and cooperating with said cathode to provide a number of individual discharge units; a connecting lead from said cylinder to the outside of said vessel; a plurality of cooperating grid electrodes arranged intermedi-' ate said cathode and said anodes, the anode of one discharge unit being disposed adjacent to the grid of the succeeding unit, said anode and grid cooperating to provide a capacity coupling unit.

9. A multiple thermionic discharge device as claimed in claim 8 in which both said cathode and grid electrodes are of cylindrical shape and spacially arranged relative to each other to provide proper coupling capacity between successive amplifying units.

10. In a multiple thermionic discharge device as claimed in claim 8, a common conducting support covered with a layer of high resistance material carrying said grid electrodes whereby said layer serves to act as grid leaks and a common lead from said support to the outside of said vessel.

11. A multiple thermionic discharge device as claimed in claim 8 comprising an extension of said grid electrodes for increasing the mutual capacity between succeeding grid and anode electrodes.

'12. A multiple thermionic discharge device as claimed in claim 8; means for increasing the mutual capacity between succeeding anode and grid electrodes consisting of a metallic shield mounted upon the grids and arranged adjacent to the preceding anode electrodes. 

